We're not talking about one specific situation, we're talking about the best tire for "wet" traction. I assume that includes riding on the road in the rain and all the possibilities that come with it.

This is my current go to tire. It rolls well on asphalt, works well in gravel and will even tolerate some dirt.
As most dual purpose things it excels at neither, but it allows me to go where I want with my bike. Sometimes when I get on a particularly smooth road, it makes a humming sound and makes me feel like the guy driving his Jeep on the highway with off-road tires. Of course, as long as the Jeep is actually driven off road too, it makes sense (many of them are all muddy and that makes me smile).

Yes on the off road stuff. Look at a Motocross motorcycle or a dune buggy tires. The reverse applies there. The knobby tread bites (digs into) the soft surface. There are many diferent trads for varying surface too. Very specialized. Even down to the size of gravel or the "type" of dirt.

Not an attempt to be argumentative, but there are really only two kinds of wet conditions. Standing water or exposed wet asphalt. There is pretty much no middle ground. There is a puddle or there is not.

If the asphalt is exposed, tread patterns are moot and a soft rubber compound provide the best grip. If there is standing water I avoid it at all costs.

This is an oversimplification.

Wet, clean asphalt after a light drizzle? I'd wager that not only will slicks have the best grip, they'll have 90%+ of their dry grip. In fact, I'd say that at normal speeds, even standing water isn't a huge concern, since we've already established that it's virtually impossible to make a bicycle hydroplane. The concern with wet traction is the unpredictability, since rain brings dirt, grime, oil, etc into the equation.

But a tread pattern will not "grip" dirt, grime and oil. That's the point. The edge of a groove in a tire won't do diddly squat to hold onto a piece of asphalt that has been saturated with antifreeze. The edge of a groove wont bite the fine silt floating on the road surface.

A hard surface will bite a tire or it won't. Adding grooves to a tire just offers the road less to bite.

The illusion that people are under is that a tread pattern or groove will "Bite" an unstable surface. It won't. Think of riding around a corner covered in dry fall leaves. Tread pattern or slick, you are going down.

So we've established that treaded tires are better for loose surfaces (such as dirt, gravel, or mud), and a slick tire is better for hard surfaces (like asphalt or concrete), but there's no in-between? The only two options are a knobby tire or a slick?

There are plenty of in between tires. They don't work as well as a slick on asphalt, and they don't work as well as a true knobby on sand, dirt or gravel. They are a compromise.

That's my only point. A slick is always better on asphalt. Always. Adding a tread pattern will never improve grip on asphalt, under any circumstances.

Now, riding a slick on a dirt road or wet grass and expecting grip is equally dumb. I know this from personal testing at high speeds.

Wheel Energy, a lab doing actual testing on bicycle tires, disagrees with your sweeping generalization.

Bicycle tires ? puncturing the myths - BikeRadar USA

https://www.wheelenergy.com/

I read that article a while ago. It was all over slowtwitch. How much is measurable? Tread "can" increase adhesion but how often and under what conditions? Are the "certain" tread designs anything any of us would like to ride? These are the type of questions I ask when I read unquantified statements like that.

I'm not saying that the lab is wrong and its great that someone is actually measuring this stuff now. I'd simply like to see these statements flushed out a bit, that's all.

I'll be the first to believe if the data is there and if it makes sense in the real world.

Yep. They disagree and make their own sweeping generalization. Including spelling and technical errors.

Between both links the only information about road tires and grip is the following.

** Mechanical grip is a product of suspension forces during acceleration. Moot in a road bicycle discussion.

They do not provide a description of their testing procedures. Nothing.

They do not state or describe their findings. Scientifically or otherwise, detailed or otherwise.

They provide zero scientific data to back up their claim. Not even in the vaguest most layman terms.

You know there is a problem when you find this statement.

When those guys have 40 plus years of real world testing, including heat dissipation numbers through contact patch and how that affects inflation levels, at different ambient temperatures, and different track surface temperatures, and how those changing inflation levels will affect wear patterns, then I'll start paying attention.

Labs are great and all. But in racing the real answers come from examining lap times. The charts can say tire "A" should provide better grip, but if tire "B" provides a reduced lap time, that is the answer that matters and tire"A" goes into the trash can.

Please, provide your own scientific results proving that slick tires are better on asphalt in all conditions.

As I've stated before, the majority of tires in the pro peloton have a patterned tread. This has virtually nothing to do with tire sponsors, because many riders choose their own tires regardless of sponsor. If we're using real-world racing as an example, it certainly doesn't prove your point.

To be clear, I'm not claiming that textured tread provides better grip in wet conditions. I'm saying that the issue is nowhere near as black-and-white as you claim. The burden of proof is on you to demonstrate that your hypothesis is correct, because you're the one speaking in absolutes.

Why are you more willing to believe that a textured tread doesn't improve group?

There are an almost uncountable number of motorcycle and car racing series that use slick tires exclusively. The only series that use DOT approved tires with tread patterns do so to keep costs and speeds down. Usually entry level series.

Formula One is the pinnacle of auto racing. As technology advanced year after year, speeds and lap times grew increasingly faster. Due to safety concerns a deliberate effort to slow the cars down in the corners was made beginning in 1998 (IIRC). In order to slow them down the sanctioning body outlawed the use of slick tires and a grooved tire was introduced.

This is simply fashion. No different that the width of your lapels and ties changing from decade to decade. Tire companies need to market their product. They do this with white walls, gum walls, red stripes, blue stripes. They also introduce "New and Improved for 2016" tread patterns. New and sexy tread patterns help sell tires. If a lab and can measure grip, (and I believe they can) we would already have arrived at the best single tread pattern many many years ago. And there would be ONLY one, because, you know, it's the best, scientifically. Tire manufacturers are not all going to use the exact same tread pattern for obvious reasons. Similarly, they won't all sell only slick tires because it does not differentiate them from their competitors.

Wheel Energy states that not all asphalt is equal or consistent. This is very true. In an effort to design a tire that will perform better on one asphalt vs another asphalt, things that will increase performance would be tire SIZE, carcass construction and flexibility, profile, and compound.

On a hard surface, reducing the size of the tire's contact patch can ONLY lead to reduced grip. That can be achieved by running a smaller tire or by introducing vacant areas (tread patterns).


Sure it is. The entire racing world agrees 100%. And has for 60+ years. There is no discussion. No gray area.

Bicycles spend so little time at max lean and high speeds that tread is an accepted feature.

Texture equals less surface area. Less surface area means less material for the asphalt to bite. Equals less grip.

So I see slick vs. tread is the new brakes and/or helmets debate.

so much for a quick question...

Any racing series that uses slick tires does so under perfect or near-perfect conditions only. Racetracks are constantly groomed and are far, far "cleaner" than any public road, other than being covered in bits of rubber. It's really, really dangerous to drive on the street with slicks. It's even dumb to drive on the street with something like a Toyo R888 or Advan A050, despite the fact that they have some tread and are DOT legal. Do you know what a Formula 1 rain tire looks like? Or what a Hoosier rain tire looks like?

Of course, none of this matters, because it's well established that trying to apply concepts learned about a 1500lb vehicle traveling at 200mph with tires 305mm-380mm wide to a 180lb vehicle traveling at 25mph with tires 23mm wide would be foolish. Cars and motorcycles are not bicycles. The weight and speed differences mean that it's impossible to say conclusively that what applies to these vehicles also applies to bicycles.

I'm not sure why you keep coming back to tread being all about fashion. It's a poorly-kept secret that the tires the pros ride are often labeled with their tire sponsor's logo but are actually made by companies like A. Dugast, FMB, or Veloflex. If slicks were as superior on all road conditions as you believe, the bicycle racing world would have embraced them by now regardless of marketing. Thus, the entire racing world does NOT agree with you. Auto and motorcycle racing agrees that slick tires provide the most grip on a dry clean track. That's it. There is far from a consensus about tread design for bicycles riding on public roads.

It's easy to simplify the situation and say that less rubber on the road equals less grip. The reality is that there are far too many factors at play to come to any conclusion without actual testing.

Of course, none of this matters because virtually any decent tire, with tread or without, will provide enough grip for the average rider. I've personally crashed a few times from having the front tire wash out, but every time was either in snow or mud.

That's completely false. Monaco is perfect? Macau is perfect? Long beach is perfect? The Isle of Man is perfect? Those are awful public roads with extremely poor surfaces. Horrible in fact. They race those circuits on slicks.

All closed circuit race tracks that I have raced on were FAR from perfect. Bumps, tar joints, repair scabs, you name it.

^ Then why do the most prestigious and fastest racing series use slicks on public road courses? Again, grooves in a tire won't help it grip a spot of oil, or a squashed rodent, or an expansion joint, or a man hole cover.

Yes. They are used when there is standing or running water to avoid hydroplaning. ALL drivers/riders will stay out on a wet track on their slicks as long as possible until they are forced to pit for grooved tires to deal with standing water.

The laws of physics and how they relate to a contact patch change when you remove and engine from a vehicle? How do the laws of physics know that the engine was removed? The forces that a bicycle tire experiences are less extreme than a car or motorcycle, but they are still the SAME forces. All the rules still apply.

You've hit the nail on the head. Thank You. Racers will often (appear to) wear/drink/eat/ride whichever brand pays the most, regardless of their personal belief of the products' superiority or not.

Just saying that won't make it true. A bicycle tire manufacturer need to sell tires, and they need something to sell those tires. Having a STAR rider on your tire helps sell it. Tread patterns are the designer logos of the tire world. It's the same with DOT approved car and motorcycle tires. Car tire manufacturers even make claims that their tread patterns are quieter and ride better than their competitor's tires. It's competition to gain market share. Nothing more.

I agree. There are millions of people who are still uneducated (< not meant as an insult) on the subject.

Because that is the reality. Improved Lap times have been PROVING this for over 60 years. If less rubber equaled more grip, racers would use narrower tires or tires with tread patterns. They don't. It really is that simple.

Bicycle races use skinny tires for the obvious speed benefits associated with the reduced weight. But they do so at the cost of cornering grip.

No, there are not too many factors. Bigger tires equal more grip. Shrinking the contact patch reduces grip. It aint any more complicated than that. A slippery, dusty, uneven road surface will reduce grip. Removing rubber from the tire won't magically change the road surface.

True. And this is why we see tread patterns on bicycle tires. The "Safety Placebo Effect" that we have all been exposed to for our entire lives, and Fashion (Marketing). People who are not involved in the racing industry or follow racing as a hobby have spent their entire lives being told by all forms of advertising that tread patterns are where grip comes from. The manufacturers are forced to advertise this way because the governments forces them to sell treaded ALL Season tires for year round use. The general public thinks slicks are slippery and dangerous. And that's to be expected because it's what they have been told their entire lives.

The absence of rubber does not create grip. It's really no more complicated than that.

Monaco and Macau are literally resurfaced every year before the race. None of these road courses are going to have the same conditions as an open road.

No one is talking about rodents, expansion joints, or manhole covers. In fact, we’re specifically talking about the conditions you encounter on a wet road. Remember, at no point have I disagreed that slicks are ideal for a bicycle on dry asphalt.
Bring up driving with slicks on the street with a bunch of racecar drivers, trackday junkies or virtually any driving enthusiasts and I guarantee they will all consider it a horrible idea. Roads are unpredictable.

No disagreement.



Physics absolutely does NOT work that way. The rules apply, but phenomena that exist at one scale do not necessarily exist at another.
Within a few minutes of use, the racecar slicks you brought up are no smoother than a textured bicycle tire. You wouldn’t consider there to be less rubber on the road because of that, would you? If we added the same texture seen on racing bicycle tires to racecar slicks, it would a) have very little impact on the grip and b) be worn away almost immediately.


Literally the exact opposite of what I said. A rider sponsored by Specialized, which has a huge budget, will ride tires made by FMB, which doesn’t advertise at all. They ride those tires because they believe they’re better for racing.



Despite your cynical belief that these companies only care about marketing, product development actual does mean innovation. All tires are not made the same.

The argument is not that less rubber equals more grip. The argument is that we don’t know the specifics of the interaction between a <1mm tread texture of unknown durometer and a road surface of varying texture and substance.
This discussion isn’t skinny vs. wide, don’t turn it into that. I’m a proponent of wide tires, but that’s irrelevant.

Imagine a hypothetical situation in which the tread pattern of a tire perfectly matched the coarse surface of asphalt. Would that tire not have a bigger contact patch than a slick? Friction is not as simple as homogeneous material against homogeneous material, although high-school physics problems present it as such. In the real world, friction has two mechanisms: adhesion and hysteresis. What that boils down to is micro (adhesion) and macro (hysteresis) structures interlocking. Asphalt has a rough texture and a pneumatic rubber tire is soft, and the interaction between the two is the reason why tires have such good grip on a road.

There are many, many academic papers published on the topic of the frictional interaction between tires and asphalt. Assuming that we know all there is to know would be foolish.

It’s no more complicated than that, in your opinion. Your only evidence showing that slicks are the best choice for a bicycle on asphalt, rain or shine, is that racecars usually use slicks.

They are, literally, public roads. literally. There is no difference. Some extremely rural, some full blown urban, with all the warts. Long Beach especially is horrific. These teams run slick tires on horrible public roads. I've been there. Please don't say the conditions can't be compared when they are identical.

That's a tall guarantee. I know dozens of guys (including myself) that run slicks on Superbikes on the road because the grip is far superior to treaded tires. I see you are in Chico. Run down to Palomar Mountain some Sunday and see what what the enthusiasts are running. Find the Acura NSX and Porsche groups and see what kind of tires they use for spirited runs. Slicks. Go to the restaurant parking lot at the top and see how many (MANY) guys have newspapers or towels hiding their tires from the CHP.

This is laboratory fantasy. A hypothetical perfect tread/road surface match will be useless in the real world as soon as you roll forward ten inches or turn left a foot and the surface contours and textures change. You have mentioned that roads are unpredictable. How could one tread pattern be useful over any real world distance when the surface changes? A soft slick's surface deforms to mate with the surface it meets, and continues to modify itself as road/track surfaces change.

Lap times (grip) for cars and motorcycles improve with slicks. You need evidence that the same would be true for a bicycle?

[MENTION=362748]SquidPuppet[/MENTION] [MENTION=178365]Young Version[/MENTION] So far its been an excellent discussion gentlemen, I must commend you both on your debating ability and on remaining very civil during the whole process. I found it very interesting.

All I know, personally, is that I've had slicks (both Continentals and Tufos) wash out underneath me many, many times, while that has never happened when using a textured tire. I'm only talking about road bike use, btw.

Cornering on bicycles is totally different than on motorcycles/cars, because power is generally not applied on a bicycle when leaning in a turn. I have lot of experience racing bicycles in wet conditions, and instead of running different tires, I and most of my fellow competitors simply lowered the tire pressure to get better grip in the corners. Also, race tires use softer rubber compounds to improve grip at the expense of mileage. So, basically I don't believe one can make a valid comparison between tire designs for motorcycles/cars vs bicycles.

Your point about power delivery is fair enough, when discussing the rear tire on corner exit. That said, there are many circumstances where a motorcycle is ridden just like a bicycle, with no throttle applied in the corner. A few examples would be a downhill corner, or a decreasing radius, or very off camber. Often a motorcycle coasts through those types of corners. So I think there are strong enough similarities to make comparisons.

I'd say comparing front tire design would be very fair since fronts aren't the driven wheel. Think of hard corner entry, leaning in, and trail braking deep to the apex. Both bike and motorcycle front contact patches experience the leaning, loading, and twisting.